Tunnels, when designed properly, are known to be one of the safest places to be during an earthquake. From a structural safety standpoint, the tunnel moves uniformly with the ground, in contrast to surface structures. Additionally, a large amount of earthquake damage is caused by falling debris, which does not apply inside tunnels. Some examples:

1994 Northridge Earthquake: no damage to LA Subway tunnels

1989 Loma Prieta (Northern California) Earthquake: no damage to tunnels, which were then used to transport rescue personnel

1985 Mexico City Earthquake: no damage to tunnels, which were then used to transport rescue personnel